Air cleaners are widely used for removing foreign substances from the air. The foreign substances can include pollen, dander, smoke, pollutants, dust, etc. In addition, an air cleaner can be used to circulate room air. An air cleaner can be used in many settings, including at home, in offices, workrooms, etc.
An air cleaner can include any type of mechanical filter element comprising a mesh, a weave, a foam, etc. An air cleaner can further include electrical air cleaning components, such as a collector cell that removes dirt and debris from the airflow of the air cleaner. A collector cell can comprise an ionizer and/or an electrostatic precipitator. The collector cell requires a high voltage power supply in order to operate. The high voltage power supply typically supplies a high voltage at a relatively low electrical current.
In the prior art, the manufacturer typically attempts to match the power supply to the collector cell. This is usually done by tuning the power supply to a specific output voltage, such as by use of a potentiometer (i.e., a variable resistor) that is adjusted to set the output voltage of the power supply. The output voltage is therefore essentially fixed, while the output current varies according to the load presented by the collector cell.
The prior art fixed output voltage produces a desired output current in the collector cell. Subsequently, a prior art air cleaner detects changes in the output current in order to detect problems such as arcing or shorting in the cell and shuts down power to the cell when such problems occur. The output current can increase greatly upon the occurrence of arcing or shorting in the cell.
The prior art has drawbacks. The output voltage, although set at the time of manufacture, can vary due to atmospheric conditions, such as the ambient air temperature and ambient humidity. Ionization of air is heavily influenced by both factors. In addition, the output voltage is also affected by assembly tolerance variations in the cell geometry. Consequently, the electrical current in the cell is difficult to set and control in a consistent fashion. Further, subsequent changes in temperature and humidity during operation can change the operating current requirements. As a result, a prior art air cleaner collector cell can operate at less than optimal voltage and current settings. This can result in poor performance if the voltage and/or current are undesirably low. Alternatively, this can result in excessive arcing and shorting (and therefore physical damage to the air cleaner) if the voltage and/or current are undesirably high. Moreover, this can result in the operation of the cell at improper times and can result in shut down of the cell at improper times.